Poe's law is very strong here.
Why anyone think it's the slightest bit professional to use it in official communications is mind boggling. It was sort of trendy for a little bit on Reddit with a certain type of abrasive and annoying American, but thankfully it seems to becoming uncool again.
It is also an extremely imperialistic word. Americans use it, it feels as if it only refers to Americans, and Google is only listening to Americans.
"youse" falls into the bad pattern of also picking up "guys" or "all" as hangers on, in my opinion, defeating the purpose. ("youse guys" being the terrible patriarchic movie Mafioso cliché, and "youse all" a terrible Frankensteinian monster I've heard far too frequently.)
"yinz" to me looks and sounds more like a weird pharmaceutical than an English word, and y'all aren't going to convince me otherwise. ;)
But of course, my opinion is biased by geography and familiarity.